Various types of locking mechanisms have been attempted in the past to secure a propeller to prevent its unauthorized removal or theft. In recent years this has become a major problem especially as the cost of propellers has escalated.
Two major problems presently exist in this type of product. One problem is the necessity to provide a locking mechanism which can be left on the shaft at all times. Many of the devices in the past have been mechanisms which must be installed when the boat and engine have been removed from the water for transportation or storage. The real problem is encountered when the boat and engine are returned to service and placed in the water for use. If the locking mechanism is forgotten and not removed considerable vibration and possible damage can occur to the propeller, shaft and engine drive train.
The second problem deals with the question of corrosion. In many cases the locking mechanism, out of necessity, is formed from dissimilar metals which causes a galvanic corrosion effect when the lock is in contact with the water. This type of corrosion is greatly accelerated when the engine is used in saltwater.
Corrosion in many cases causes failure or weakening of the lock materials and difficulty in removing the locking mechanism when desired so that the propeller can be either changed, repaired or removed when necessary. Thus, when the owner desires to remove the propeller and is prevented from doing so by the locking mechanism, the entire advantage of utilizing the mechanism in the first place has been lost with any further use of a locking device rendered questionable.
The present invention is directed to a unique type of locking arrangement which prevents the unauthorized removal of the propeller and yet maintains a waterproof condition for the internal parts which prevents corrosive action and allows the mechanism to be easily removed and installed when desired. In turn, the mechanism can remain on the shaft at all times and is quite inexpensive to manufacture and maintain.